Live center tool



u 26 1947 E, E. RglNscH 2,426,566

uva mman TooL Filed April 19, 1945 2m. www l' /8 :a zy. EIT M IINVENTOA BY REZMSLCH.

Patented Aug. 26, 1947 Erich E. Relnsem clli'cagp, Ill. i, y application April 19, 1945, serial Np. 589,199

2 Claima 1 i AThe object of 'this invention is to provide a new (c1. sla- 33) the center point pressed'rearwardlywithinthe and 'improvedflathe center with which' extreme precision may be secured with a high degree ofV uniformity that will hold the work firmly and accurately in place during all conditions and during-'all changes of temperature vof the stock being operatedon.

A further object of this invention is to provide i a new lathe center having a, work'receiving center vwhich rotates with the stock being worked upon Vand an automatic adjustment and take-up on the pivot bearing incorporated within sothat l the center will rotate vaccurately and'without chatter at all times.

A stillV further object of this invention is'to provide a revolving lathe center which is constructed in such` a manner thatl a lubricant, such as oil, is carried without the possibility of leakage.

nAnother object of this invention is to provide a live centerV tool for a lathe, said center tool having a tapered shank portion at the rear end thereof, and adapted to be positioned in the tail stock spindle of said lathe, said tool having an enlarged portion'or housing at its forwardY end,said tool having a spring pressed center pin which Aprojects beyond said housing and fitted therein to extend rearwardly into a bore within said shank,

the rear end of said center pin provided with a. y

outer housing. y .Y y f Figure IV is a sectional view of the stationary housing and shank portion of the lathe center. Figure V is a longitudinal view of the center point and shaft, `with the rear portion ybroken away and shown in cross section. y

Figure VI is a view, partly in section and partly in elevation, showing abearing :with an oilre ,taining groove.` y l y Figure VII is a viewin .elevation showing the :lock-collar adapted to fit on the rear shaft portion of the live center. l Y l In the drawing reference'numeral I0 'designates Ava tapered lathe center which isr adapted to fitinto the tail stock ofj'a lathe in the usual Y manner.

socket to retain a ball-bearing type of thrust y bearing which is further retained in the` bore of said shank and which is also inA contact with a steel washeror fiat surface member in lsaid bore, said bore also having a compression spring therein for pressing said washer into contact with said ball-bearing and further for pressing said movable pin outwardly, said vtool having means for holding said pin against the outward pressure of said spring, however, permitting said movable center point to recede within the housing against the pressure applied to the rear end thereof, said shank having means for varying the tension upon said spring to compensate for any shortening in the length thereof incident to replacing parts or regrindlng said center point.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in n the appended claims. i

The invention is illustrated in the accompanying drawings, forming part of this application, in which:

Figure I is a, longitudinal view of a preferred embodiment of this invention.

Figure II is a sectional view of the same. Figure III is a sectional viewof the same with In Figures II and IIIthe tail stock spindle or ram thereof, as the case may lie,v is illustrated generally at I2 and hasv the usual recess I 3 therein to receive the center point construction. V'Ihe lathe center is made up of a body or'socke't I4 ham'ng a shank I5 whose periphery is provided with a taper so asto provide a fit withthe recess AI3. The head end portion IB forms a part of the f body I4 and is considerably enlarged as best seen in Figures II and III.

The body I4 is hollowed out to provide a bore IS in the forward end of head I8, and bore 2| in the central and rear end thereof. The shank I5 is provided with a bore 22 in the forward and central portionv thereof, and with a threaded hole 20, in the rear end thereof.

A shoulder 23V is arranged in the rear end of bore I9 adjacent to bore 2|, and a shoulder 24 is arranged in the bore 2| adjacent to'bore 22. The rear portion of bore I9 and the forward end portion of bore 2| is shaped to receive the hollow collartype bearing 25, while the bore 2| is arranged to receive the' cylindrical lock collar 26 positioned upon the rear cylindrical portion 30 of l .center 21. The forward end of bore I9 is arranged to receive the enlarged head portion 28 of the center 2'|, the left washer 3|, and the enlarged portion of collar 25, while the bore 22 is adapted to receive the cylindrical portion 3Ilv of said center 2l which is directly behind the Acentral portion`29 thereof, said portion 29 is adapted to receive the collar 25, while said portion 30 is adapted to receive the collar 26.

The tail portion 32 of the shank I5 is reduced as at 33 and is drilled or hollowed out to form the bore 2|), said bore being tapped or threaded, to receive adjusting plug' 34 threaded into the rear end'fthereof. The plug 34 is provided with a key seat 35 to receive a tool for adjusting said plug to crowd or release a washer 36 against the rear end of a spring 31 which is positioned in bore 22. Said spring 31 regulates the tension. thereof against washer 39 which is in contact with thrust ball-bearing 39 positioned in bore '22 and in socket 40 formed in the rear end of the portion 30 of center 21. Y

The ball-bearing 39 is in the bore 22 between socket 40 and the flat washer4 38 and is in combination with the spring 31 to absorb the thrust sufficient to support the load of the work, and align the center point with the work, preventing wiggle therein. The center 21 maintains alignment and is capable of running in a bath of oil, since oil is fed through oil hole 42 into bore 2| which is provided withclosure `plug 55. The oil travels through a vertical passageway 43 to a horizontal oil passageway 44 and then in each direction therethrough, forwardly to a vertical passageway 45 where the cil contacts the interior vof bearing 25, said bearing having an oil groove 46 as shown in Figure VI.l Theoil is sealed in bore I9 by closure plug 55 and felt washer 3|. When the oil-travels rearwardly in passage 44 it contacts the bearing 39 in socket 4|). The center 21 has a mark or groove -41 on its surface,

, the running parts being enclosed in oil, said lathe said mark to guide the operator as to the movement of said center pin.

As the stock being worked upon becomes warm and expands longitudinally, it presses upon the center point 21 and forces the shaft 30 rearwardly, compressing the spring 31, as well as compressing thefelt washer 3| in bore I9. The lock collar 26 travels along'with shaft 30 since it is held in place by set screw 50. Bearing 25`is held in place by set screws 5| and 52, and by this arrangement bearing 25 and collar 26 become separated as clearly4 shownin Figure III.

'I'he socket 40 and bearing 39 may be arranged so that the ball may Vrotate in the socket, however, it is more often desired that the ball may be non-rotatably carried in the socket. By the latter arrangement the center 21, with parts 29 and 30 thereof, and the bali 39, will rotate freely, said ball providing a point contact bearing center should give longservice.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts provided that such changes fall Within the scope of the appended claims.

Having thus described my invention, what I claim as new is:

1. In a compensating center, the combination of a stationary support, a chamber formed in the forward end thereof, an axial bore formed in the central portion thereof, a live center pin located in said chamber and extending into said bore, a stationary bearing in said chamber'supporting said pin, alockcollar located on saidl pin, a ballbearing located at the end of said pin, a bearing plate in contact with said ball-bearing, a spring located in said bore and in pressing contact with tained between th'e revolving center and assoas described above.

To utilize cemented-carbide tools today and with the high speeds of work revolution, the fixed saidV plate, and means for lubricating the stationary bearing and all moving parts.

2. In a compensatingV center, the combination of a stationary support, a chamber formed in the forward end thereof, an axial bore formed in the central portion thereof, a live center pin located in said chamber'and extending into said bore, a stationary bearing in said chamber supporting said pin,.a lock collar located on said pin, a ballbearing located at the end of said pin, a bearing plate in contact with said ball-bearing, a lcompression spring located in said bore for pressing said plate into contact with said bail-bearing and further for pressing said center pin outwardly, means for holding said pin against the outward pressure of said spring but permitting said movable pin to recede within the chamber, against the pressure applied to the rear end thereof, lubrieating oil located within said chamber and oil passageways connecting said chamber with all moving parts.

ERICH E. REINSCH.

REFERENCES CITED TheA following references are of record in the file of this patent:

UNITEDV STATES PATENTS Number Name Date 979,034 Rowe Dec. 20, 1910 1,747,385l o1scn Feb. 1s, 1930 1,993,809 Schnelle Mar. 12, 1935 2,056,586 Rohm oct. 6, 1936 2,140,565 Svenson Dec. 20, 1938 

